Abstract: In this paper, we had first analysed the possibility of uncoupling C₃ point group, two most possible sagittal plane of the wave was calculated, C₁ point group is an invariable transform group, and on the basis of koerber's result the distribution rule of uncoupled piezoelectric surface wave modes in point group was investigated, then we can see the C₃ point group is uncouled because of its lower symmetry, and a preliminary conclusion is reached that the distribution rule of uncoupled piezoelectric surface wave modes in point group exhibit some periodicity, i.e. uncoupling reappears in every crystal system.